Method of applying coating materials



I- 1948' JQS. SMYSVER 2,447,374

METHOD OF APrLYIgc; Comma uumnns Original Filed April 25, 1954 3Sheets-Sheet 2 yjl.

I NVEN TUR Aug. 17, 1948. .LS. SMYS ER IETHOD OF APPLYING comma u'rnannsOriginal Filed April 25, 1934 3 Sheets-Shut 3 INVEN run Jmzs 62 3017550,Br 604M115 7kw'r (m/0; firm/m.

* Patented Aug. 17, 1948 UNITED STATES PATENT OFFICE METHOD OF APPLYINGCOATING MATERIALS Continuation of application Serial No. 722,288, April25, 1934. This application October 25, 1939, Serial No. 301,294

2 Claims. 1

This invention relates to a method of applying particles and variousforms of comminuted materials to a base member, and to the resultin!product.

This application is a continuation of the copending application of JamesS. Smyser, Serial No. 722,288, filed April 25, 1934.

The principal objects of the invention are to provide a novel method forapplying particles and finely divided materials, such, for example, asflock, linters, and the like fibrous material, abrasive particles, etc.,to one or more surfaces of a base member, such as a piece of sheetmaterial; to provide means for controlling the manner and rate ofapplication or disposition of the particles so as to obtain a uniformlycoated product having predetermined characteristics; and to providemeans whereby unlimited lengths of sheet material may be coatedefliciently and progressively, on either or both sides, more uickly,densely, uniformly and cheaply than by any apparatus and/or methodheretofore used.

Other objects of the invention are to provide a strong and flexibleproduct having a dense, homogeneous, villous finish simulating theappearance of either suede or a pile fabric; and to provide a finish ofany desired density wherein the major portion of the fibers are disposedat substantially the same angle relative to the surface of the basesheet with their ends firmly embedded in an adhesive coating carriedthereby.

Further objects relate to the mode of operation of the method, and willbe apparent from a consideration of the following description andaccompanying drawings which exemplify different embodiments of theinvention.

In accordance with the present invention the surface (or surfaces) ofthe base member, or article to be coated is first rendered adhesive, asfor example by the application of a suitable cementitious material, suchas rubber cement, wax, paramn, glue, or the like adhesive. When thuscoated the base member is passed through an electrostatic field set upbetween one or more pairs of oppositely charged electrodes, and duringits passage through the electrostatic field the par-' ticles to beapplied are carried in a uniformly dispersed formation into the fieldeither by gravity, a current of air, or in any other suitable manner.

Preferably the particles being conveyed to the field are charged in anysuitable manner with the same charge as that of the electrode projectingthem against the base member, and to this end they may be passed througha metallic screen or the like member which is connected in the circuitof the projecting electrode. When thus charged, the particles, uponentering the electrostatic field are projected against the adhesivesurface of the base member more uniformly and efiiciently, and with muchgreater force than would otherwise be possible. Furthermore, theindividual particles are more effectively aligned in the direction ofthe lines of force of the electrostatic field and, due to the increasedforce with which they are projected against the surface of the basemember, are more deeply and firmly embedded in the adhesive surface ofthe base member. Moreover, movement of the charged particles toward theadjacent or projecting electrode is greatly minimized, if notsubstantially eliminated, and consequently considerable waste iseliminated and the eiiiciency of the method and apparatus is appreciablyincreased.

The construction and arrangement of the electrodes is such as to providean electrostatic field of uniform flux density which extends across thepath of the surface of the article to be coated and at an angle to itspath of travel. The position of the individual particles relative to thesurface of the base member may be controlled and/or varied by adjustingthe relative position of the electrodes so as to attain the desireddirection of the lines of, force of the electrostatic field relative tothe surface of the base member. To this end one or both of theelectrodes may be adjustably mounted so that their position relative toeach other may be varied.

The electrostatic field may be produced by a suitable source ofpotential such as aKenotron or the like alternating current rectifier, astatic machine, meohanical rectifier, or any other source which may besusceptible to control. The potential impressed upon or across theelectrodes may vary within wide ranges, depending upon the character ofthe material to be deposited, the desired rate of deposition, etc., andthe usual types of control instrumentalities maybe employed to providean electrostatic field of the desired characteristics.

The rate 'of deposition or application may be so controlled as toproduce a coated product of any desired density by varying the quantityof particles supplied, the rate of travel of the base member through thefield, and/or the electrical characteristics of the field, i. e., theflux density, voltage across the electrodes, etc. To this end suitablemeans may be employed to control the rate of delivery of the particlesand the rate of electrical circuits or circuit to provide for theadjustments necessary to attain an electrostatic having a series ofpointed members or prongs secured thereto and arranged as shown in Fig.2.

The electrodes are arranged in pairs -lll, 4| and l2, l3 and may beconnected to any suitable source of potential as hereinafter described.The

elements of each pair are disposed on opposite field suitable for theapplication or deposition of the particular type of material to beapplied.

In the drawings:

Fig. 1 is a diagrammatic side elevation, in section, showing a suitableapparatus;

Fig. 2 is a diagrammatic plan view of the apparatus shown in Fig. 1, themeans for feeding the particles to be applied being omitted;

Fig. 3 is a schematic diagram illustrating one arrangement of theelectrical connections;

Fig. 4 is a graphic representation of a pulsating current used inconnection with certain forms.-

of apparatus herein shown Fig. 5 is a fragmentary section showing apiece Fig. 11 is an enlarged fragmentary section 1 showing a specimen ofsheet material after being coated in accordance with the presentinvention.

The embodiment shown in Figs. 1 and 2 comprises a coating apparatus ID,a deposition apparatus designated by the numeral II, and a windingmechanism l2. The coating apparatus may be of any type suitable forapplying a coating of adhesive such as rubber cement, wax, glue,paraflln, or the like cementitious material to one or both surfaces of abase member or sheet material S, and as here shown comprises atank ortrough l9 having guide rolls l5, I1, 20, 2| and 22 to conduct the sheetmaterial through a fluid bath 23 of suitable adhesive, and squeeze rolls24 and 25 to remove excess adhesive and distribute the coating uniformlyover the surfaces of the sheet S. The temperature and fluidity of thebath 23 may be controlled in any suitable manner as by steam coils 26.The winding apparatus l2 may be of any conventional form and is hereshown as comprising a. guide roll [3, a winding drum l4, and a reel 15,upon which the coated sheet material is wound. Suitable means (notshown) may be provided to regulate the speed of the winding drum l4 andthus control the rate of travel of the sheet material S.

The deposition apparatus H comprises a boxlike structure or housingpreferably having uprights or walls of suitable electricalnon-conducting material which define the deposition zone metallic barsecured to a suitable support and sides of the path of travel of thesheet S and are preferably inclined at an angle to its line of travel soas to provide an electrostatic field which extends diagonally across thepath of movement of the sheet S. The purpose of this inclinedarrangement is to insure a more even coating when the comminutedmaterial is fed to the electro static field from the top.

Suitable means are provided to conduct the material to be deposited onthe sheet S into the electrostatic fields set up between each pair ofelectrodes and to this end hoppers 5|! and 51 may be arranged directlyabove electrodes 40, I and 42, 43, respectively. If it be desired tocoat one side of the sheet S only, the hoppers may be arranged todischarge the coating material into a zone between the projectingelectrode and surfaceof the sheet to which the material is to beapplied. Where both sides of the sheet S are to be coated, the hoppersmay be arranged to discharge the particles on'both sides of the sheet 8or, if desired, one hopper may be arranged to discharge the material onone side of the sheet and the other hopper on the opposite side, theparticular arrangement depending upon the connections of the electrodesfor the most effective results. I

At some convenient location between the hoppers 50, SI and theelectrostatic fields, there may be provided means for imparting anelectrostatic charge to the particles to be applied and to this endmetallic screens 52 and 53, or the like, may be mounted beneath thedischarge openings of the hoppers and 5|, as shown in Fig. 1, or, ifdesired, these screens may be integral with the hoppers. Each of thescreens are connected to the negative electrode or to the negativeterminal of a suitable source of potential so that the particles as theyemerge from the screens have the same negative charge as that of thenegative or projecting electrode. Suitable means (not shown) may beemployed to control the rate of delivery of the particles from thehopper so that the density of the coating applied to the sheet materialmay be varied as desired.

Fig. 3 shows how the electrodes maybe connected for use with a pulsatingcurrent (graphically represented in Fig. 4) such as may be'derived froma two-tube Kenotron rectifier,'or a continuous (non-pulsating) currentsuch as may be derived from a static machine, mechanical rectifier witha suitable condenser, a high voltage generator, or the like.

In the arrangement shown in Fig. 3, the electrodes 40 and 43 areconnected to each other by a conductor and by a conductor" to a suitablesource of potential, here shown as a Kenotron rectifier designatedgenerally by' the numeral 60. The electrodes 4| and 42 are connected toeach other by a conductor 51 and to the ground by a conductor 58. Withthis arrangement the conductors 55 and 5-6 are preferably connected tothe negative terminal of the Kenotron or other source of potential andits positive terminal may be grounded by means of conductor II. theground and conductor 68, at which point the main circuit branches intotwo circuits, one of which comprises electrodes 42 and 43 and theconductor 55, the second branch circuit comprising the conductor 51 andelectrodes 4| and 40. The conductor 58 connects the branch circuits tothe negative terminal of the Kenotron and thus completes the maincircuit from the Kenotron to the'electrodes.

This arrangement is particularly suitable for use when both sides of thesheet S are to be coated as it will be noted that the negativ orprojecting electrodes 40 and 43 are on opposite sides of the sheet S andthe intensity of the electrostatic fields established between each pairof electrodes is always the same. When this arrangement is used inconjunction with the apparatus shown in Figs. 1 and 2, the screens 52and 53 may be connected to the electrodes 60 and 43, respectively, sothat the particles discharged into the electrostatic field are firstgiven a negative charge. The hoppers 50 and 5| and the screens '52 and53 are preferably positioned so that the charged particles are deliveredinto that portion of the electrostatic field between the projectingelectrode and the adjacent surface of the sheet to be coated.

In using the apparatus shown in Figs. 1 and 2 to carry out the process,the sheet material S,

such as a piece of fabric (Fig. 5), is drawn from the supply roll l8,through the bath 23 where a coating H (Fig. 6) of adhesive such as glue,paraflin, rubber cement, wax or the like is applied to both surfaces.While the adhesive coating is still tacky the sheet is guided betweeneach pair of electrodes, as indicated in Figs. 1 to 3. The electricalconnections are adjusted to produce the desired potential across theelectrodes and thus establish an electrostatic field of the desiredstrength and intensity. After having made these adjustments the materialto be applied is fed from the hoppers 50 and 5| at a predetermined rateand after passing through the screens 52 and 53 where the individualparticles receive a negative charge, they are then carried by gravityinto the electrostatic field. When material such as fiock, linters andthe like fibers, as well as the various forms of abrasive material suchas Carborundum, pumice, tripoli, etc., constitute the coating materialbeing applied, the individual particles upon entering the electrostaticfield, due to their elongate nature, become aligned in the direction ofthe electrostatic lines of force and are uniformly projected orbombarded against the adhesive surface of the sheet S so that their endsare deeply and firmly embedded in the adhesive coating at substantiallythe same angle and their projecting portions are disposed in substantialparallelism relative to each other. Due to the initial charge impartedto the particles, they tend to repel each other and become dispersed sothat upon being projected against the adhesive surface of the sheet Sthe individual particles are spaced relatively to each other. As theindividual particles align themselves with their major axes coincidingwith the direction of the electrostatic lines of force, they may beapplied to the sheet S so that their major axes are disposed at anydesired angle relative to the surface of the sheet and consequently agreater number of particles per unit area may be applied to the sheetand with greater uniformity than is otherwise possible. When thusapplied, their embedded ends are held in spaced relation to each otheron the sheet S and by reason of capillary action and the removal of theiilm of air surrounding the particles the adhesive creep! up or risesalong their sides forming a mensicus about the embedded ends of eachindividual P rticle.

After having received a coating of particles on one or both surfaces,sheet 8 is guided out of the deposition zone and passed between a pairof ultra-violet lights L and L' or other suitable means operative todischarge or neutralize the static charge carried by the coated surfacewithout causing sparking. After removing the static charge on the sheet,it is then wound up on the reel I5. During both the coating anddeposition operations the sheet 8 is held under slight tension bythepull" of the winding drum and reel. The density of the coating may bevaried, as desired, by varying either the rate of travel of the sheet 8,the rate of delivery of the particles from the hoppers 50 and BI, orboth, and the stren th of the electrostatic field may be variedaccordingly.

When applying fibrous material at a relatively low rate, a potential ofthe order of 15,000 to 25,000 volts may be used, although I prefer touse potentials from 100,000 to 500,000 volts, particularly where heavierparticles are being applied or where the rate of application is to begreatly increased, the particular voltage depending upon the characterof the particles, the rate of travel of the sheet, and various otheroperating conditions.

Figs. 7 to 10 show a form of deposition apparatus particularly suitablefor the application of flock, linters, asbestos fiber. wood pulp fibers,fine abrasives and the like materials, to an adhesive coated surface ofa base member. In the embodiment shown in Figs. 7 and 8 the sheetmaterial S is drawn from the supply roll over a spreader roll 8|provided with a spreader blade 82 which is operative to distribute afluid or plastic adhesive 83, such as rubber cement or the like,uniformly over the suriace of the sheet S. After having received acoating of adhesive of suitable thickness, the sheet is drawn over orabout a guide member which constitutes a part of the depositionapparatus. Thereafter the sheet is drawn downwardly between a pair ofdischarging electrodes 84, 84 connected to a suitable sourceof highpotential alternating current, then over a guide roll 86 and wound on areel 81, as in the previously described apparatus.

The guide member preferably comprises a plate electrode interposedbetween two sheets of electrical non-conducting material such asBakelite, the upper sheet or layer 80 having a smooth surface and beingprovided with a rounded or beveled edge as shown in Fig. '7. Thenegative electrode 90 is disposed opposite the end of the electrode 85and is arranged so as to establish a field whose lines of forceintersect the path of travel of the sheets at any desired angle.Preferably the length of each electrode is willcient to provide anelectrostatic field having a width corresponding to that of the sheet S.

Asupply hopper 91 is disposed above the electrostatic field and isconstructed and arranged to deliver the fibrous material onto a screen92 or the like device interposed between the field and the hopper. -Theelectrical connections are shown schematically in Fig. 7 wherein aconductor 95 connects the screen 92 and the electrode 90 to the negativeterminal of a suitable source of potential designated by the numeral 96,the positive terminal being grounded by a conductor 91 or connected tothe electrode 85, as desired.

The electrode ll may be grounded by a conductor II or otherwiseconnected to the conductor 01, and suitable means such as a controller99 and rheostat I may be provided to control the potential and flow ofcurrent in the circuit. If desired, a voltmeter IOI may be connected inthe circuit in the usual manner. The electrodes 04, 00 when connected asshown in Fig. '7, establish an alternating electrostatic field acrossthe path of the coated sheet and are thus eilective to discharge orneutralize any static charge carried by the sheet. The operation of theapparatus is substantially the same as that of the previously describedapparatus, it being understood that the present arrangement is designedto coat only one surface of the sheet 8 at one time.

In the embodiment shown in Fig. 9, the cementitious material is appliedto the sheet S in the same manner as in the embodiment shown in Figs. 7and 8. In place of the guide member and plate electrode shown in Figs. 7and 8, a roller electrode I is used. The roller electrode provides aguide roll about which the sheet S is drawn on its way to the windingdrum or reel (not shown) and may be connected to the ground orotherwise, as in the previously described apparatus. The negativeelectrode I01 comprises a metallic screen member which is shaped toprovide a substantially horizontal portion I08 through which theparticles discharged from the hopper I 09 may pass, and a dependingportion IIO disposed opposite but parallel to the roller electrode I05.The supply hopper I09 is disposed above the horizontal portion I 00 ofthe negative electrode so as to discharge the particles onto itshorizontal portion. The negative electrode is connected to the negativeterminal of the source of potential and the usual control devices may beprovided as in the previously described apparatus.

The embodiment shown in Fig. 10 is somewhat similar to that shown inFigs. 7 and 9 but is particularly designed for use in applying particlesto a sheet having an adhesive coating which comprises a thermoplasticcementitious material,

such as wax, parafiin, etc., which must be maintained in a relativelyfluid or tacky condition during the deposition operation in order thatthe ends of the particles may be firmly embedded therein. The apparatusembodies all the essential elements shown in Figs. 7 to 9 but in placeof the electrodes shown therein, a metallic block I I4 and rotor II5 areused. The block I I4 constitutes the positive electrode and preferablycomprises a metallic casting having a series of longitudinally extendingducts or channels IIB which may be connected to a steam or hot watersupply (not shown). The outer walls of the block I I 4 which contactwith the sheet material are smooth'and the adjacent corner is preferablyrounded or beveled to provide a suitable guiding surface over which thesheet S is drawn. The rotor II5 constitutes the negative or projectingelectrode and preferably comprises a. cylindrical screen or gratingsupported on a circular plate which is rotatably mounted on a stationarytubular shaft Ill. The tubular shaft II! is provided with a radiallydisposed axially extending slot coextensive with the longitudinal extentof the screen and facing away from the electrode H4. A conduit II!having an elongate, horizontally extending, flaring mouth or entrance Idisposed in radial alignment with the slot H8, is disposed closelyadjacent to the electrode 5, as shown, and may be connected to asuitable suction fan or'the like (not shown).

' for discharging the static charge from the coated sheet may beemployed. During the deposition operation the electrode II! iscontinuously rotated, compressed air being introduced into the shaft II1 and discharged through the slot III, and the electrode H4 ismaintained at a predetermined temperature by the fiow of steam or hotwater through the ducts H0. The force of the air striking against thescreen or grating of the electrode H5 is sumcient to remove anyaccumulations of oriented fibrous material or other particles and carrythem into the conduit I20, thus keeping the negative or projectingelectrode relatively free of oriented material.

Fig. 11 shows a coated sheet material produced in accordance with thepresent invention. The backing sheet consists of a sheet of heavy paperI28 and the fibers of the coating I21 are adhered thereto by a layer ofadhesive I26 and are disposed at an angle of 45 to 60 relative to thebacking sheet I28, thus presenting an appearance resembling suede.

The products are greatly superior to those made in accordance with theprior practices wherein the fibrous material is deposited on an adhesivesurface of a, backing sheet by means of a current of air or by gravity.In such products the individual fibers are heterogeneously disposed onthe surface of the adhesive and hence do not assume any definiteposition relative to each other. Consequently, such products do notpossess the dense and uniform characteristics nor the attractiveappearance or finish of those made in accordance with the presentinvention. Moreover, the wearing qualities of such products are greatlyinferior to those made in accordance with the present invention due tothe fact that the individual particles are not embedded to a sufilcientextent, if at all, in the, adhesive, and as the body portions and theends of the individual fibers provide the surface of the product, theindividual fibers are soon worn away or are easily dislodged from theadhesive and hence expose uncoated areas of the binder. In the productsmade in accordance with the present invention the individual fibers,being firmly embedded in the adhesive, are not easily dislodged and astheir ends constitute the major portion of the surface of the product,they effectively resist wearing. Furthermore, due to the fact that amuch denser coating may be applied to the adhesive surface of thebacking sheet, there is a greater number of fibers per unit area toresist wearing and abrasion, and consequently the product of thisinvention will outwear those made in accordance with the priorpractices.

While different desirable embodiments of the present invention have beenshown, it is to be understood that this disclosure is for the purpose ofillustration only and that various changes and modifications may be madewithout departing from the spirit and scope of the invention as setforth in the appended claims..

Certain phases of the invention are disclosed and claimed in theco-pending application Serial No. 375,432, filed January 22, 1941, whichissued to Patent No. 2,287,837 on June 30, 1942.

What is claimed is:

1. The process of coating to provide a suedelike surface which includesas steps thereof feeding a carrier or backing and applying an adhesivelayer to a surface thereof, and depositing on said adhesive layerparticles of finely divided fibrous material under the influence of anelectrical field whose lines of force are directed so as to orient theparticles with their major axes at an angle of from about 45 to 60 withrespect to the backing, attaching the ends of said particles to saidadhesive layer and leaving the opposite ends free, thereby forming thesuede-like surface for said carrier or backing.

2. The process of forming suede-like surfaces which includes as stepsthereof feeding a carrier or backing and applying an adhesive layerto asurface thereof, and depositing on said adhesive layer particles offlock under the influence of an electrical field whose lines of forceare directed so as to orient the 'particles with their major axes at anangle of from about 45 to 60 with respect to the backing, attaching theends of said particles to said adhesive layer and leavin: the oppositeends free, thereby forming the suede-like surface for said carrier orbacking.

GRANITE TRUST COMPANY, By IRVING L. SHAW,

Vice President, Executor of the Last Will and Testament of James S.Smyser, Deceased.

10 REFERENCES crrm The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 209,805 Goodall Nov. 12, 18781,194,874 Peterson Aug. 15, 1916 1,575,165 Hopkinson Mar. 2, 19261,710,747 Smith Apr. 30, 1929 1,788,600 Smyser Jan. 13, 1931 1,855,869Pugh Apr. 26, 1932 1,886,234 Meissner Nov. 1, 1932 15 1,902,921Underwood Mar. 28, 1933 27,3 7 Schacht Jan. 7, 1936 2,027,308 SchachtJan. 7, 1936 2,047,525 'Ihode July 14, 1936 2,173,032 Wintermute Sept.12, 1939 a 2,173,078 Heston S pt- 1939 FOREIGN PATENTS Number CountryDate a 339,913 Great Britain Dec. 18, 1930 396,385 7 Great Britain AM.1, 1933

